1. Features and Management System of Experimental Strain Groups

Management is performed as rice genetic stocks reservation project by Plant Breeding Laboratory in cooperation with Genetic Resources Development Research, Graduate School of Agriculture.
The rice experimental strain groups maintained in our laboratory have the following features.

Strains holding genes recognized by classical genetics and distinctly located on the RFLP map.

Unique collection of numerical and structural variants of chromosomes

Recombinant inbred lines and chromosome segment introgression lines of subspecies and alien species created in the course of rice genome research are rich resources for genetic research and not seen in other place.

The strains of item (iii) will become more enriched since the present research work in our laboratory is concentrated on the item (iii). Management of strains of items (i) and (ii) is performed by the experts consisting of professors and associated professors.

2. Outlines of Rice Experimental Strain Groups

Plant Breeding Laboratory takes care of the following rice experimental strain groups under National Bioresource Project (as of May 2004). 95% of them are original product of our Laboratory and completed except chromosome substitution lines, which are under development and evaluation. Besides, there are about 1000 lines under development.

Use: Gene mapping and a tester for various genetic experiments. "Taichung 65" is convenient material for the transformation experiment as its efficiency for callus differentiation and redifferentiation. Origin & building procedure: F1 between Taichung 65 and FL strain was backcrossed to Taichung 65.

Features: Uniformity of heading date is useful for genetic experiments.

From the progeny of hybridization between autotriploid and diploid of "Nipponbare", trisomics having various morphological characteristics were chosen and trisomic analysis was performed by crossing to marker gene strains. Primary trisomic series with genetic background of "Nipponbare" was constructed.

Desynaptic variants induced by MNU treatment on fertilized eggs of "Kinmaze" and "Taichung 65" were crossed to their diploid parent, and from their progeny, primary trisomics series having each variety as genetic background were established based on the morphological characteristics.

Features of strains: Distinctive characteristics of grain shape, panicle shape and plant type are associated with the concerning extra chromosome or area of extra chromosome.

construction procedure : From the progeny of the cross between "Asominori" (japonica) and "IR24" (indica), selfing generation has been advanced by Single Seed Decent Method (SSD) to the F12 generation at present.

Features: RIA strains are genetically homozygous and can be used 7 for QTL analysis.

Features: IAS strains cover almost entire genome area with substitution segment of "Asominori" chromosome and their genetic background became essentially that of "IR24", recurrent parent. They are efficient experimental populations for the analysis of traits controlled by multiple genes. IAS is expected, together with its reciprocal counterpart AIS, to be used effectively for gene interaction analysis.

Construction procedure : In the fourth backcross generation to "Asominori", BC3F1, and its selfing generation, BC3F2, RFLP marker selection was performed to establish chromosome segment substitution line. Substitution chromosome segments of donor parent "IR24", overlapping among strains, covers entire genome. Candidate plants were chosen in respect of uniformity of background. In BC3F1 generation 66 plants were chosen based on 116 RFLP markers. From their 400 selfed progeny plants, finally 91 chromosome segment substitution lines were established. They have been kept by selfing and reached to BC3F6 generation at present.

Features: AIS strains cover almost entire genome area except a part of Chromosome 3 with substitution segment of "IR24" chromosome and their genetic background became essentially that of "Asominori", recurrent parent. They are efficient experimental populations for the analysis of traits controlled by multiple genes. They may be used for construction of NIL and map based cloning. Using this material, principal genes concerning hybrid sterility have been identified. AIS is expected, together with its reciprocal counterpart IAS, to be used effectively for gene interaction analysis.

Features: GLU-ILs covers almost entire nuclear genome of O. glumaepatula in both cytoplasmic groups, though there are some lacks in chromosomal area. There is strong hybrid weakness found in O. glumaepatula cytoplasm, but the introduction of weakness recovery gene (Rhw) on Chromosome 8 makes the maintenance of lines possible. In the process of GLU-ILs establishment, gene loci were identified for several seed shattering and heading date genes. They benefit the gene analysis of specific traits to O. glumaepatula. These strains may be useful to analyze the cytoplasmic genomes as they have both of different cytoplasms.

Features: MER-ILs covers almost entire nuclear genome of O. meridionalis in both cytoplasmic groups, though there are some lacks in chromosomal area. In the process of GLU-ILs establishment, gene loci were identified for several awned and shattering genes. These strains may be useful to analyze the cytoplasmic genomes as they have both of different cytoplasms.

Construction procedure : BC3F1 was obtained by backcrossing of F1 to "Taichung 65" three times. From BC3F1 and its selfed progeny BC3F2, chromosome segment introgression lines was established by marker selection. Substitution chromosome segments of donor parent O. glaberrima, overlapping among lines, cover entire genome. Strains have been kept by selfing and reached to BC3F7 at present.

Features: GILs successfully introduced chromosome segments originating in O. glaberrima to "Taichung 65", except a part of Chromosomes 1,7, 5, 10 and 12. The QTL analysis of major traits of O. glaberrima is in progress now. Heading date genes and hybrid pollen sterility genes have been clearly identified and located on the genetic map.

3. Present Status of System Construction for Seed Multiplication, Management and Distribution

The present situation of system construction for above mentioned rice resources possessed by Plant Breeding Laboratory, Kyushu University is as follows:

4. Database Construction and Presentation to The Public

Results of the research performed in our Laboratory, i.e. the mutant gene loci determined on the RFLP map and the morphological photograph pictures of various mutants will be presented to the public. They are to be accessed at http://www.agr.kyushu-u.ac.jp/lab/plantbreed/mutant/